Residual bioefficacy of diflubenzuron (Dimilin®) against larvae of dengue vector, Aedes aegypti (Linnaeus) in Kuala Lumpur, Malaysia

The residual bioefficacy of diflubenzuron, a chitin synthesis inhibitor, was evaluated against the larvae of a dengue vector, Aedes aegypti. Dimilin® WP (wettable powder), 25 % w/w was used in this study. Diflubenzuron (0.1112 mg a.i./L) was used to treat a set of plastic containers placed both indoor and outdoor. Thirty laboratory-bred early 3^rd instar larvae were introduced into each container and observed daily. The number of emerged adults was calculated and recorded. The indicators of effectiveness of the IGR for these studies were: (i) duration of residual activity, and (ii) percentage of emergence inhibition (EI). Generally, the treated indoor containers showed complete emergence inhibition up to 6 weeks, while treated outdoor containers indicated that the emergence was completely inhibited up to 4 weeks. The duration of effectiveness which caused 50% emergence inhibition under indoor and outdoor conditions was up to 12 weeks and 6 weeks, respectively. On the whole, diflubenzuron appeared to perform better under indoor than outdoor condition. Application of diflubenzuron is simple and straightforward, as well as an effective method of long term control of mosquito larvae.